It is known to provide a concentrated oxidant for fuel, as for example, oxygen, in addition to air to the combustor utilized in gas turbine engines. See, for example, U.S. Pat. No. 3,092,964 issued June 11, 1963 to Martin et al. As explained therein, the concentrated oxidant may be provided to the combustor under certain specified conditions as, for example, under conditions in which ignition is uncertain or impossible or in conditions wherein it is difficult to maintain combustion such as at high altitudes. At other times, and generally for the vast majority of the operational cycle of such a turbine, the combustor will be provided only with air and fuel.
The use of a concentrated oxidant such as oxygen under the conditions mentioned previously is effective for overcoming ignition or combustion difficulties under the specified circumstances. However, because of the high reactivity of the concentrated oxidant typically used, separation of the burning fuel and oxidant into a mainstream and one or more eddies or backflows, also of burning fuel, may damage injector components. In particular, because of the high heat generated under such circumstances, the resulting combusting of fuel with the concentrated oxidant may result in the exterior of injector components as, for example, the fuel injection nozzle, being burned and/or eroded, thereby shortening their useful life and lessening the reliability of the gas turbine in which they are employed.
The present invention is directed to overcoming one or more of the above problems.